Hi guys! I have been trying to fix this for almost a week now and I cannot seem to find the problem! I have a MacBook 5,1 (aluminum) which came originally with Leopard installed. I tried doing a clean install with Mountain Lion and something went terrible wrong and it couldn't install. I had to go find the old DVD with Leopard installation and make a clean install with it. After that I tried installing SL with a bootable USB drive (I downloaded the dmg from the internet, can´t find that DVD anywhere unfortunately). The install won't work, I get a message saying Mac OS X can't be installed in this computer. I had purchased Lion on the app store when I was running SL before and I have here the dmg but I can't upgrade from Leopard to Lion with it. Now I'm the the middle of a big problem that I can't manage to fix! Any ideas? Much appreciated!